Detectives from Mountjoy Garda station are investigating the double stabbing. The gardai’s National Bureau of Criminal Investigation are also involved in the probe.

A source said: “It’s very early days and the incident could have been caused for a variety of reasons but it would be unusual for someone with no gangland connections to attack an individual who has been charged with an offence linked to the Kinahan and Hutch feud.

“Gardai will try and establish if there was any previous tension between those involved and this also depends on the victims cooperating. Investigators will examine all avenues in this attack because of who was involved.

“It could have just been a fight over the smallest of issues and it doesn’t take much for someone in the prison to arm themselves to settle a dispute.

“The chief suspect is known for propensity for violence and has used knives in the past to attack people all over Dublin.”

Although Fox has been charged with Gareth’s murder, we can also reveal gardai have identified other suspects in the chilling killing which was captured on CCTV.
Chief Supt Pat Leahy, who has recently been promoted to Assistant Commissioner, vowed to catch others linked to the killing.

The senior officer added: “They will be brought to account because there is no other outcome.

“There will be people who will feel trapped between both sides and they may come forward because we are the only people who can guarantee a future.

“I think these people will rue the day they took on the legitimacy of the State.”

Since the murder of The Monk’s brother Eddie, investigators in the north inner city have made 16 arrests, charged two people with murder, recovered 11 firearms and conducted 60 searches.

Fox’s close pal Taylor was jailed for life after he was convicted of the murder of Paul Kelly, 26, in Clontarf, north Dublin, in 2007.

Taylor’s dad, Michael Snr, was shot dead at a caravan site in Donabate in 2011 — in revenge for Kelly’s killing.